Trailer draft mechanism



Feb. 6, 1940. vSHERMAN 2,189,183

TRAILER DRAFT MECHANISM Filed Aug. 17, 1936 2 Sheets-Sheet 1 l2 4INVENTOR ll 7' AI- hur S. eserman 14 ZTORNE Feb. 6, 1940.

Filed Aug. 17, 1936 A. G. S. SHERMAN TRAILER DRAFT MECHANISM 2Sheets-Sheet 2 Smaentor Ari/nu Q6. \sierman B5 a (Ittorneg Patented F b.6,1940.

'raA Lna DRAFT MECHANISM Arthur G. S. Sherman, Detroit, r r

Application August 17, 1936,.Serial No. 96,383

' s ains;1614280433;

. This invention relates to trailer draftconnec tions, and particularlydraft connections exercis ing control of trailer brakes. i i

In applying brakes to a trailer, the required braking effort dependslargely on severalhighly variable factors, such as trailer momentum(largelydetermined by load), road traction conditions, et cetera. Iftrailer deceleration materially exceeds that of the towing vehicle,undue wear on the trailer tires and undue strain on the draft connectionresult, while if the towing vehicle decelerates too slowly, it willoverrun the towing vehicle and may skid the latter from its course. Suchfactors entail an automatic control of the trailer brakes, and suchcontrol may be advantageously exercised by adevice operated inconjunction with the draft connection to the trailer. I

An object ofthe invention is to utilize a limited lostmotion travel of acoupling pin connecting a towing'vehicle and trailer to actuate avalveor other control device, whereby energization of the:

trailer brakes will automatically resultfrom deceleration" of :thetowing vehicle, when the brakes of the latter are applied.

Another object 'is to provide a draw bar having an improved leaf springformation, particularly adapting it to motor vehicle trailer use. a Afurther object isto provide a coupling fo trailers "affording a limiteduniversal play between a towing'and trailing vehicle and permitting aquick and easy coupling or uncoupling of such vehicles. I

These and various other'objects the invention attains by theconstruction hereinafter described and'illustratedin' the accompanyingdrawings,

wherein:

Fig. 1 is. a fragmentary perspective view of a trailer base frame and ofmy improved draft connection engaged therewith.

arrangement. 1

Fig. 3 is a front end Fig.-2 is a top plan. view of the coupling view ofthe same.

Fig. 4 shows the same in longitudinal vertical;

section, taken on the line 4-4 of Fig. 2.

Fig. 5 is a diagrammatic view of a trailer and towing vehicle, shown inelevation, with my improved trailer brake control mechanism installed.

In theseviews,'the reference character I designates a pair of forwardlyconvergent draw bars,.

secured at their rear ends by bolts 2, or the like;

I to opposite sides ofa trailer base frame 3, and

interconnected rigidly and preferably integrally at their front ends.Thus, as best appears in lying bar by clips l or the like.

upstanding from the coupling member.

Fig.2, said bars areformed of a single lengthbf stock formed atthejuncture of the bars with an arcuate, short-radius bend la. Theforward portions of 'thebars rigidly carrya coupling meniber 4,comprising a pairof arms 5,rearwardly diverged and downwardly channeledto receive theforward portions of the bars, the channels of said armscommunicating to receive the arcuate connection la. Bolts Gor othersuitablefastenings rigidly connect the bars to said arms.

bars are preferably of spring steeLpermittinga limited, shock-absorbing,up and down move:

ment of theirfrontends, and asshown, the rear portion of each bar isreinforced by a superposed bar lb, engaged by the securing means Zandhaving its forward portion attached to The forward portion of thecoupling member 4 forms an approximately spherical socket 8 in con-.

junction with alatchboltll removably fitted in a pin II is engaged insuchsocket. The opening l2, through which thepin ll projects ismaterially smallerthan the ball head, prohibiting downward escape of thelatter. Upon removal D m-a? U Q I groove in the front face of saidmember, and the ball head ll] of a downwardly projecting couplin'g ofthe latch bolt; the coupling pin is forwardly detachable from thecoupling member, said openinglz being extended for that purpose to thefront face of saidmember, and an opening {3 being formed above the latch"bolt for-the same purpose.

The latch bolt is normally held in pla'ce by a pair of headed pins I 4passed through its end portions and engaging the coupling member aboveand below-said bolt. The heads .of such pins seat onthe top face ofthecoupling member and are diametrically bored to receive a retainer l5,engaged between said heads with a lug i6 Prefer ably such retainer islatched in its effective position byengaging'one'of its ends by a hookll terminally formed on an arm l8 spring-connected to its other v end.As shown, theretainer, said hooked arm, and a coiled spring connectionl9.

between the two, are heavywire. I i

An important feature of the invention is a proformed of a single lengthof vision for a slight forward and back lost motion i of the couplingpin ll relative to the coupling member-ll, and utilization'lthereofftoapplyand release the trailer brakes (not shown)", when the socket 8 iselongated in the direction of draft to afford the ball head In apredetermined play in.

required. Thus,ras bestapp'ears in Figs. 2 and 4,,

the underthat direction. During normal transmission of draft, this playis taken up, as shown, by the thrust of the ball head against the latchbolt 9. Under this condition, a plunger 20, slidable in the couplingmember rearwardly and axially of the ball head, projects into the socket8, responsive to a spring 2i acting on a lever 22 to which the rear ,endof such plunger is pivoted. The lever is fulduct 26. Then, however, thebrakes of the tow-' ing vehicle are applied, the resultant decelerationof such vehicle engages the ball head i ii with the rear face of thesocket 8, or, at least, effects a rearward shifting of the ball head,proportionate to deceleration of the towing vehicle. The resultant,rearward actuation of the plunger 26 overcomes the spring 2i, and actson the valve,

through the lever and link, to open the duct 25 and permit a fluidenergization of the brakes. Thus the trailer brakes (Fig.5) will beapplied with a force automatically proportioned to decel 301m eration ofthe towing vehicle. 7

The described retainer transmits no draft stresses andis quickly andeasily releasable from the pins Hhalth'cugh its accidental escape is'sipositively prevented by the spring-latch action of the hooked arm l8.Upon removal of the retainer, either or both of the pins l4 may bewithdrawn to uncouple two vehicles (Fig. 5). Itis, of course, preferableto withdraw only one of said pins, thelatch bolt 9 being then free toswingto the dash line position shown in Fig. 2.'

To permit such swinging, the rear face of said bolt may be rounded asindicated at 28, in intersectingat least one end of the bolt.

The described ball and socket coupling establishes an exceedingly strongand safe connection between a towing vehicle and trailer, whileaffording separation thereof by a simple manipulation. The universalplay secured by the construction avoids frequent, abrupt, and heavystrains on the draft connection during travel along rough roads ortrails, and the spring na-- ture of the draw bars absorbs many heavystresses that would otherwise react on the towing vehicle.

interposed in the duct 26 to interrupt, at will,

automatic control of the trailer brakes. Such interruption is desirableon various occasions, as

in rearwardly actuating the two vehicles, de-

scending a sharp incline, or when no trailer is attached. Asillustrated, the handle 35 is associated with the instrument board 3'!ofthe towing vehicle. I

, The illustrated arrangement renders the trailer brake controlmechanism independent of the mechanism (not shown) controlling thetowing vehicle brakes, and thus. permits conjoint or independent brakingof the two vehicles, as occasion warrants.

The invention is presented as including all such modifications andchanges as come within the scope of the following claims.

What I claim is:

1. A draft connection comprising a pair of vertically flexible,resilient draw bars attachable at their rear ends to a trailer andforwardly converging, a yoke member having divergent arms channeled toreceive the forward end portions of said draw bars, means rigidlysecuring said arms to said bars, and a coupling pin engaging the yokemember forwardly of the draw bars. I

2. A trailer draft connection comprising a pair of resiliently flexibledraw bars, convergently extending forwardly from a trailer, means forrigidly attaching said bars to the trailer, and means rigidlyinterconnecting the forward ends of the bars, whereby any flexure of thebars must occur in unison.

3. A V-shaped draft connection comprising means carried at the apex ofsuch "connection for applying. draft thereto, and means for securing thecorresponding ends of said connection rigidly and in horizontally spacedrelation to a member to be drawn, said connection being flexible, up anddown, about its rear ends.

ARTHUR G. s. SHERMAN.

